NASA's Hubble Space Telescope continues to reveal various stunning and
intricate treasures that reside within the nearby, intense star-forming
region known as the Great Nebula in Orion. One such jewel is the bow
shock around the very young star, LL Ori, featured in this Hubble
Heritage image.

Named for the crescent-shaped wave made by a ship as it moves through
water, a bow shock can be created in space when two streams of gas
collide. LL Ori emits a vigorous solar wind, a stream of charged
particles moving rapidly outward from the star. Our own Sun has a less
energetic version of this wind that is responsible for auroral displays
on the Earth.

The material in the fast wind from LL Ori collides with slow-moving gas
evaporating away from the center of the Orion Nebula, which is located
to the lower right in this Heritage image. The surface where the two winds
collide is the crescent-shaped bow shock seen in the image.

Unlike a water wave made by a ship, this interstellar bow shock is a
three-dimensional structure. The filamentary emission has a very
distinct boundary on the side facing away from LL Ori, but is diffuse on
the side closest to the star, a characteristic common to many bow
shocks.

A second, fainter bow shock can be seen around a star near the upper
right-hand corner of the Heritage image. Astronomers have identified
numerous shock fronts in this complex star-forming region and are using
this data to understand the many complex phenomena associated with the
birth of stars.

This image was taken in February 1995 as part of the Hubble Orion
Nebula mosaic. A close visitor in our Milky Way galaxy, the nebula
is only 1,500 light-years from Earth. The filters used in this color
composite represent oxygen, nitrogen, and hydrogen emissions.

March 6, 2002
Image Credit: NASA and the Hubble Heritage Team (STScI/AURA)